Longeron for aeroplanes



LONGFJRON FOR AEROPLANES G. CAPRONI Filed Dec. 24, 1927 5 Sheets-Sheet 2 BY Q.

AT'TORNEY Oct. 8, 1929.

G. CAPRONI LONGTJRON FOR AEROPLANES Filed Dec. 24, 1927 3 Sheets-Sheet 5 lNl/E/V TOR Gianni Caproni A r TORNEY edges of a parallelepipedon.

Patented Oct. 8, 1929 UNITEDgSTATES PATENT OFFICE GIANNT GAPRONI, or ROME, ITALY, ASSIGNOR, BY MESNE ASSIGNMENTS, To CURTISS- CAPRONI CORPORATION, OF WILMINGTONHDELAWAR-E, A CORPORATION OF DELA- WARE Application filed December 24, 1927, Serial No. 242,452, and in Italy December 29, 1926.

The present invention concerns certain improvements to the longrons or wing spars of aeroplanes by means of which it is possible to obtain, besides a greater simplicity and solidity of construction, a better distribution of the stresses.

This result is substantially obtained by forming the longrons of four metal tubes or section irons connected between each other by means of rigid struts andwire diagonals with adjustable tension. Advantage is also taken of this construction, in order that the connecting knot serves for stiffening purposes, said knot being shaped in such a Way that the lines of action of .the stresses all pass through the central axis which serves as support for the strut.

In the accompanying drawings, which show schematically and by way of example some embodiments of the object of invention; I

Figs. 1, 2 and 3 represent a first embodiment of the longron in front view, in top view and in cross section, according to line AB of Fig. 1,

Figs. 4, 5 and 6 show respectively, in front view, in top View and in cross section, according to line GD of Fig. 4, and embodiment of the connecting knot of the longron, with t-hestrut and thewdiagonals Figs. 7 and 8 show a cross section and a front view of another embodiment of the connecting knot of the longron, with th strut and the diagonals.

Figs. 9 and 10 represent a cross section and a front view of a modification of the connecting knot according to Figs. 7 and 8.

Throughout the figures the same elements are indicated with the same reference nuinerals. 1

As seen from Figures 1 and 3, each longron consists .Of four-tubes 1, the axes of whichare disposed according to the 1 On the .said tubes, at convenient intervals, are fastened tubular elements or pipes 2, with brackets 3, provided with holes 4 into which are bolted screw tension members 5 which serve to tighten at will the stays 6 consisting of wires or round bars. Tubes 1 are spaced between each other by means of cross members formed of tubular elements 8, introduced into the projections 7 of pipes 2.

In order to rigidly connect this type of dongron with the strut. and the diagonals, there is provided the device represented in Figs. 4,. 5 and 6, substantially consisting, in this first embodiment, in sleeves 9 slipped over the tubes, 1 and stiffened transversely by means of Cross-tubes 10 connected with plates 11, and vertically by plates 12 and cross-tubes 13. All the platesare lightened by wide apertures suitably shaped and in. correspondence with the centre they are perforated in order to support by means of rigid ribs a large tubular pivot14.-on

which, as will be explained further on, by

means of rings or similar devices it is possible to fasten the stays not represented in these figures, designed to connect the upper wings to the lower ones of the aeroplane.

Another embodiment of this device is represented in Figs. 7 and 8, in which 15 is the tubular strut ending at its lower extremity with a stirrup 16, which serves to fasten the strut on a double transversal plate 17 by means of hollow pivots 18. According to this embodiment the device consists of four U- shaped irons 19, arranged in correspondence with the edges of a parallelepipedon. These U-shaped irons are held together by means of four plates 20 rendered lighter by apertures 21 and fixed at their extremities on U-shaped irons, then bent upon the edges of the same, so that the corresponding laps of said irons and the corresponding plate, as far as concerns that portion of it which lies between said laps, are situated on the same plane. The said plates have preferably a rectangular shape, and along the upper semi-diagonals there are fastened the oblong attachment plates 22, provided at the upper portion with hollow pivots. 23, on-which by means of rings 24 are anchored the stays 25 which connect the wings between each other.

In order to better distribute the stresses in the modification according to Figs. 9 and 10,

the connecting plates 20 are interrupted attheir centre in order to leave a passage for hollow pivot 26, on which by means of rings 27 the stays 28 are anchored. In this manner the stresses are centered, and the material may be used to better e'fi'ect. As will be seen from the drawings, the other parts of the de-- vice, indicated with the same reference numerals, have remained substantially unaltered; nevertheless many other changes vmight be introduced without abandoning the fundamental idea of the invention.

Claim r In combination, a prismatic longron ,for aeroplane wings, the four edges of which consist of tubes connected by means of tubular couplings with transverse .stifienin and staystherebetween, a tubular jomt' consisting of four sleevesadapted for receiving the ends of the longitudinal tubes of the longron, plates connecting said sleeves, each vertical connecting plate being provided with stiflening ribs and having an opening to allow the passa e of a pivot whereby to. anchor struts an stays connecting the upper and lower wings of an aeroplane.

In testimony whereof I signature this 9th day of December 1927.

GIANNI CAPRONI.

tubes havev aflixed my 

